The leader of the United Auto Workers union has rejected a third tier of lower wages for members who make auto parts. Speaking Wednesday at the union’s national bargaining convention in Detroit, President Dennis Williams said the UAW already has too many tiers of lower wages. Williams was responding to reports that General Motors Co. and Ford Motor Co. may propose a third tier of pay. He already is under pressure from union members to end a second tier of wages that’s about half the $28 per hour made by longtime workers. He told delegates that he heard people talking...